This invention relates generally to an automotive headliner having an integral cavity and a method for making such a headliner.
Inside vehicle roof constructions sometimes include laminated headliners. Such headliners are used in many types of vehicles including passenger cars, vans, buses, trucks, trains and airplanes. Headliners are incorporated into vehicle roof constructions for a variety of reasons including aesthetics, sound absorption, energy absorption, and concealment of electrical wiring harnesses and air vents.
Materials currently used in headliner construction include particleboard, fiberboard, plastic board, scrim, fabric, plastic, various foams and resin-bonded chopped glass fiber. In some headliners, layers of these materials are joined together into a single laminate structure using lay-up-molding techniques. For example, some headliners are constructed using glass reinforced polyester resin laminated to a rigid urethane foam layer and covered by a soft urethane foam backed fabric. Other headliners are thermoformed laminates that include a polystyrene foam layer sandwiched between layers of kraft paper or polymer film material and covered with soft polyurethane foam-backed fabric. Some constructions eliminate the paper or polymer film covering from such laminates and substitute a non-woven fabric batt adhered to one or both sides of the foam layer. Still other headliners, rather than being layered constructions, are simply molded from a single layer of a composition such as fiberglass reinforced polyester resin.
Headliners are typically contoured to conform to the dimensions of the vehicle roof structure they are intended to cover. Their dimensions are also contoured to flow into adjacent interior vehicle trim panels, pillars and other such structures to present a pleasing, finished aesthetic appearance to vehicle occupants.
In U.S. Pat. No. 5,340,425, issued Aug. 23, 1994 to Strapazzini, the inventor proposes that headliners could be constructed to incorporate molded-in inserts of various kinds to include sound proofing material or decorative carpet-like material.
In addition, it is known in the art for headliner assemblies to include one or more electrical wiring harnesses. The harnesses are attached to hidden upper surfaces of such headliner assemblies using fasteners that route the wiring harnesses to a variety of sockets for the electrical accessories mounted to the headliners. The headliner assemblies are then mounted to a vehicle roof and an interconnecting wire harness in the vehicle is connected to one or more of the harnesses attached to the headliner assembly.
For example, U.S. Pat. No. 5,309,634, issued May 10, 1994 to Van Order et al. and assigned to Prince Corporation, discloses a headliner or roof panel that includes a variety of clips and mounts for wiring, lamps and the like. The Van Order et al. patent describes the roof panel as being formable from any one or more of a number of molded polymeric materials. The patent also discloses that the molded roof panel can be covered by a foam layer and a decorative outer cover. However, neither the Van Order et al. patent nor the Strapazzini patent disclose a headliner or a method for making a headliner with structures that can direct airflow in or out of a vehicle interior and/or support energy absorbing materials.
British patent application no. 1,115,212, published May 29, 1968, discloses an automotive headliner with a lower cushioning layer spaced from an upper roof covering by longitudinal ribs. The cushioning layer, roof covering and ribs define air ducts for supplying air to and removing air from the vehicle interior. According to the British application the ribs may be integrally formed with the cushioning layer but must be assembled to the roof covering in a separate step.
It is also known in the art for headliner assemblies to include a duct that is disposed on an upper surface of the headliners. Outlet registers are mounted in holes formed in the headliner at spaced locations. The duct directs airflow from a vehicle heating, ventilation and air conditioning system into a vehicle passenger compartment through the three air outlet registers. In such systems, the duct is formed separately from the headliner and is fastened to the headliner during manufacturing by such means as gluing.
It is also known to use blow-molded materials to form certain parts of instrument panels. An example of such a use is shown in U.S. Pat. No. 5,527,581, issued Jun. 18, 1996 to Sugawara et al. and assigned to a Japanese supplier of blow moldable materials. The instrument panel disclosed in the Sugawara et al. patent includes a core part having blow-molded sections that are formed from a parison. The parison is fixtured in a blow mold to form integral cavities in the form of airflow ducts in the instrument panel.
What is needed is a headliner configured to support such items as energy absorbing foam, passenger compartment airflow, and electrical wiring while presenting a continuous, unencumbered aesthetic appearance to vehicle occupants. What is also needed is a cost-effective method for making such a headliner.
In accordance with this invention an automotive headliner assembly is provided that includes a cavity formed into the substrate between upper and lower substrate surfaces to provide a receptacle for wiring, foam and the like or to provide a duct for directing airflow. The headliner assembly is configured to line the roof of the passenger compartment of a vehicle. The headliner assembly comprises a unitary substrate configured to be mounted to a vehicle in a position generally covering a lower surface of a passenger compartment roof. The lower substrate surface is disposed opposite the upper substrate surface. The substrate comprises a moldable material. A decorative cover may be supported on the lower substrate surface.
According to another aspect of the invention, the cavity comprises an air duct and the headliner includes an air inlet opening positioned to receive air from a vehicle air handling system. An air outlet opening is spaced from the air inlet opening and disposed in an underside surface of the headliner assembly to direct air from the vehicle air handling system into the passenger compartment. The air duct extends between and connects the air inlet opening and the air outlet opening to provide gaseous communication between the air inlet opening and the air outlet opening. Because the air duct is formed into the headliner substrate, the headliner assembly includes fewer parts and its fabrication is greatly simplified.
According to another aspect of the invention a directional air outlet register is disposed in the air outlet opening.
According to another aspect of the invention the cavity comprises an elongated conduit and the headliner includes a cable inlet opening disposed adjacent a peripheral edge of the headliner assembly to receive electrical or fiber optic cabling from a vehicle electrical or fiber optic system. A cable outlet opening is spaced from the cable inlet opening and is disposed adjacent a fixture supported on the headliner assembly to allow an end of the cable to be connected to the fixture. The cable conduit extends between and provides a channel between the cable inlet opening and the cable outlet opening.
According to another aspect of the invention, foam is disposed within the cavity. The cavity may include an inner wall that envelops the foam. The foam may be energy-absorbing foam to enhance the ability of the cavity to absorb passenger head impact forces. The foam may be an acoustic energy-absorbing foam to reduce noise levels within the passenger compartment.
According to another aspect of the invention additional foam-filled cavities are disposed in an array at spaced locations where passenger head impact is likely to occur if passengers are subjected to sudden vertical acceleration components.
According to another aspect of the invention the cavity is integrally formed in the substrate.
According to another aspect of the invention, a decorative outer cover is disposed on a lower surface of the substrate. A foam layer may be included between the lower surface of the substrate and the decorative outer cover.
According to another aspect of the invention, a method is provided for constructing a headliner. According to the method a blow mold is provided, the blow mold having a contoured portion shaped to complement the desired exterior contours of the headliner substrate to be formed. The contoured portion includes an enlarged region corresponding to a desired cavity position in the substrate to be formed. A molten parison is then extruded into the hollow portion of the blow mold and the parison is expanded into conforming contact with the contoured portion of the blow mold by injecting gas into the molten parison. The molten parison is then allowed to harden into the headliner substrate and the substrate is removed from the blow mold.
According to another aspect of the inventive method, the molten parison is provided between open halves of a two-piece blow mold. The two blow mold halves are closed together around the molten parison before fully expanding the molten parison.
According to another aspect of the inventive method, a layer of foam is provided on a lower surface of the substrate and a layer of cover material is provided on a lower surface of the foam.
According to another aspect of the inventive method, foam is provided within the cavity.
According to another aspect of the inventive method, foam is provided within the cavity by first inserting one end of an injection nozzle. Foam is then injected into the cavity through the nozzle and the nozzle is withdrawn from the cavity.
According to another aspect of the inventive method, the molten parison is extruded.
According to another aspect of the inventive method, the molten parison is expanded by inserting a blow pin into the molten parison, injecting the gas into the parison through the blow pin and removing the blow pin from the parison.